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Harnessing the Power of Ocean Waves

July 22, 2021


A conversation with Dr. Tom Denniss, Co-Founder and Executive Chair of Wave Swell Energy, Australia.


"[W]ithin 10 years, our technology will have a lower cost than [wind and solar] technologies. We've got to get there yet, but that's where we're aiming."

Elena: First of all, thank you for agreeing to this interview. It means a lot to me that you've accepted my invitation. I am blown away by your story because I find myself at this stage in life in which I'm supposed to decide what to do with my life. I'm supposed to choose a path, and it always seems so final to me. I find it refreshing to learn about your story because you've thrived in so many different fields. I'd say you've packed several lives in one life, and I hope I can say that of myself one day. But we'll get to that later. For now, I'd like to talk about Wave Swell Energy, the company you co-founded in 2016. Could you explain what kind of technology you are developing, how it produces energy from waves, and when you think it will be marketable or more widely available?


Dr. Denniss: OK, well, the technology itself essentially works like an artificial blowhole, a big underwater cave that's open above. So the waves pass by and they cause the water level to rise and fall inside the cave chamber in that case. And that displaces the air above it, forces it through the turbine and sucks it back in through parts of the turbine. Our system is a little bit different from previous examples like that, in that we have what's called a unidirectional system, and it only operates on the downstroke, which you may think will only halve the amount of energy, but it actually increases the amount of energy for reasons that are due to some complicated physics. So that's sort of how it works.

When will it be commercial? Well, it's just right on the cusp of being commercial at the moment. We're certainly expecting to see a big uptake in the technology in the coming years. I guess in the U.S., there's a lot of interest out of Alaska for the technology. The U.S. Department of Energy conducted a major study recently identifying where the major wave energy resources are along U.S. Coastlines. And by far, Alaska was the one that had the greatest potential. So I had a call two hours ago with the Alaskan people I've been dealing with. You might be surprised and be hearing soon about what will be happening, hopefully, in the U.S. in terms of this technology. In two weeks time, I have to be part of an interview with your PBS network. They're running a story on the technology as well. That won't air for a few months, but you could be hearing news about this technology from the mainstream media in the U.S. before too long.


Functioning of the converter units Source: Daily Mail


Elena: I read that the U.S. Department of Energy had given a grant to the University of Oregon for a project on the Pacific Coast. Is that part of the same project?

Dr. Denniss: That’s for a thing called PacWave. They're paying to run electrical cables out. It's quite a way out. I think it's about ten miles or so out to sea, in very deep water, so that project or program won't be applicable to our technology because we're much closer to shore in shallow water. But we're aware of it, there are several teams worldwide working on wave energy, but the project you mentioned is only for deep water, floating technologies.


Elena: I see. Well, given that seventy one percent of our planet is covered by water, it would seem that marine-based energy is worth investing in. You just pointed out there are several teams working on that worldwide, with different technologies. And yet, from what I have read, they all seem to have something in common, which is their high production costs. And there's also the problems with location, as you were just starting to mention. To what extent have those factors been roadblocks for the wave energy sector?


Dr. Denniss: There have been many efforts over the last few decades. The first wave energy patent was taken in 1799, but the really serious efforts have been made only in the last three decades. The problems it's encountered are three-fold. There's the conversion efficiency, that is, how much of the energy in the waves you actually convert. Many technologies are quite low in that regard, maybe only five percent or less gets converted. So that's a problem.

There's also the problem of survivability. That's probably been the main problem. You're always going to encounter some storms and some big waves from time to time. And many technologies haven't survived in those conditions.

The third other major obstacle has been accessibility, that means getting to the devices to be able to operate and maintain them. Many have been floating in water, but with the high tech components on the seabed, one hundred feet underwater, five miles offshore. And, you know, all you need is for one little thing to go wrong and you have to take divers out to fix it. They have to go down one hundred feet, you have to have decompression chambers on board, and all this sort of things. So, accessibility's a major problem. What we've managed to do is to address all of those problems.


WSE unit installed at Grassy, King Island (Tasmania) Source: Wave Swell Energy


Dr. Denniss: Firstly, our conversion efficiency is much higher. We convert around a third or more of the energy, and we hope to be getting up to half of all the energy in the waves into actual electricity. So that's a pretty high conversion rate compared to other wave energy technologies.

In terms of survivability, well, we're in shallower water, closer to the shore. And at this stage, the technology, at least the bit of technology in the water, consists of a big lump of concrete, which doesn't go anywhere. So it survives very, very well, and, I should add to that, that when you are in shallow water, the maximum size wave you can see on the device is lower as well because waves will break when their height is about 80 per cent of the water depth. So let's say we're in five meters of water, then a wave cannot be higher than four meters because it would have broken before then, that is, it would have broken further out. That minimizes the maximum type of force you can have on the structure, and helps survivability as well.

The third problem is accessibility. Because we're close to the shore, all our high tech components, the only moving parts, exist above the waterline. So it's very easy to access for maintenance and operations, not only because it's close to shore, but because it's above the waterline. We don't need divers or anything like that. When you combine all of those things together, you get a technology that is much more cost effective. We've had an independent scientific team assessing the potential for our cost of energy into the future. And the results are very, very encouraging. Effectively, it'll take a while to get there because all energy technologies start out more expensive and then come down in price. They come down pretty rapidly, as wind and solar certainly have in recent times. Solar is now less than one hundredth of its cost compared to when it began, about 40 years ago. So that's less than one percent of what it used to cost. The independent scientific report we got suggests that, within 10 years, our technology will have a lower cost than any of those technologies. We've got to get there yet, but that's where we're aiming.

Elena: My understanding was that wave energy was decades behind other renewable energies, but, from what you're saying, your progress is actually faster.

Dr. Denniss: Well, it's faster than wind and solar managed at the same time, but we're not at the same point as they are. Both wind and solar now have more than seven hundred thousand megawatts of capacity installed worldwide. That's a fair bit of electricity production, but it accounts for less than 10 percent each, probably more like five percent each, of the world market of electricity. It will take quite a while to get to that level, but this report indicates we should reach cost parity with wind and solar before the end of this decade. So, in other words, we will get to where they are in one decade, while wind and solar took three to four decades to get to where they are now.


Elena: Once you get to that level, do you think wave energy will be able to compete with wind and solar?

Dr. Denniss: Oh, yeah, absolutely. Not only will it be equal to their cost, but, in a little bit more time, it will have a lower cost than wind and solar, It will be the lowest cost form of energy, but also a high quality energy because it's more predictable and more consistent, and that makes a big difference as well. Solar energy is great, but it does have its issues. For example, if you're producing a lot of energy from a solar farm and suddenly a cloud comes in front of the sun, then that production can plummet very quickly, and it's hard for the electrical grid to cope with that. So with wave energy, you know that if it's operating now, you will still have roughly the same in the next hour and you can predict how quickly it'll drop off or pick up. It's not quite as easy with solar or wind. Wind's probably somewhere in between.

WSE unit installed at Grassy, King Island (Tasmania) Source: Wave Swell Energy


Elena: Well your confidence gives hope. But thinking about the footprint of your converter units, how would you describe the current sustainability of the technology? Mainly in terms of potential ecological disturbances and impacts on wildlife, but also on emissions from production, maintenance, etc. And also, how are you working to make your technology more sustainable, and what is your prediction on the future of the technology's sustainability?


Dr. Denniss: The beauty of our technology is that there are no moving parts in the water, nor any oils or other contaminants involved. In fact, fish view it as a sort of artificial reef, congregating around the device. This attracts other sea life, such as dolphins, penguins, and seals. So, there are no detrimental effects in regard to the environment. The technology is very benign. We’re actually looking at making the technology even more sustainable by using recycled plastics in its construction. In fact, our preference is to recycled plastic from the ocean. It would be great to extract plastic from the ocean and convert it into a sustainable product that then extracts energy from the waves in the ocean while protecting our coastlines from the effects of erosion caused by climate change.


Elena: That was very interesting, thank you. I can't wait to see how both Wave Swell and wave energy in general do in the near future. Now, if you'll indulge me, I would love to pause and rewind, and spend some time in the past. I'd like to hear about your professional career starting from the beginning, and then progressing up to the point where you are now. Could you narrate how you went from each phase to the next, what inspired you, what frustrated you, and, essentially, how you went from teaching math to being a leading expert and entrepreneur in ocean energy?

Dr. Denniss: Well, it wasn't planned, but pretty early on I decided that there was no need to choose a career when you're 18 or whatever, and then stick with that for the rest of your life. I guess it's pretty common now for people to move between careers, but it wasn't so much back then. Certainly, the generation before me, you know, they had jobs for life, or they just did not move out of their chosen career. Not very often, at least. So, straight out of school, I actually took on a traineeship as a chemical engineer, but I only lasted a month because I hated it. And so I quit and I decided to go to university full time to become a teacher. And I did that. And so I spent six years teaching, and I really enjoyed that. It was very, very fulfilling, but towards the end, I thought, "I don't know that I want to just do this for the rest of my life. I have some other interests."

So I left and managed to get into a PhD program at the University of New South Wales here in Sydney. And as part of that, because I had been a teacher, they were happy to put me on as a lecturer. I think you generally call them professors in the U.S. At the same time, I was doing my PhD, so I spent four years doing that. And I probably would have been happy to continue there at least a bit longer, but at the time, Australia was going through a bit of a phase, cutting back on Universities, so the dean of the faculty called me, and not just me, many other people... I didn't have any seniority at all, so I was told that, unfortunately, the policy was "last in, first out". They had to cut people. It was those who were the last ones to be employed. So essentially, I was told I wouldn't have a job after a certain time. That time frame wasn't stipulated, and I hadn't lost my job or anything, but I knew that at some point in the future that would happen. So I just decided to be proactive and go out and look elsewhere.


University of New South Whales Source: UNSW

Dr. Denniss: I managed to get a job at Australia's leading investment bank, which I stuck at for five years. And that was interesting and I enjoyed it. During that time, some of the people I met there, well, as you're probably aware, investment bankers tend to have a bit of money, and some of them were interested in finding the next best investment to put it into. And I just happened to mention my ideas about wave energy technology, which I'd essentially come up with on the side while I was doing my PhD. And they said, well, let's put some money into it.

And so they invested. Initially, I think it was one hundred thousand dollars. And so I basically had two jobs at the time, my job at the bank and my job trying to get an early stage wave energy company off the ground. And I was able to do both for a while, but it became obvious that I couldn't work the way I was working. There was too much interest building in the energy, and, after two consecutive 20-hour days, on the third day, I just said I can't do this anymore. I have to do one or the other, and the investors agreed to fund me going into wave energy full time, which I did. And then, because it was pretty early in those days, we ended up taking on venture capital. And venture capitalists have a policy of replacing founders of companies with their own people. And so that happened even though I could see the problems associated with that. And in the end, that company had issues due to upper management. And so that was after I'd taken the decision to run around the world. Why did I do that? Well, I wasn't so needed in the company at the time, or at least I was told that, or given the impression that, everything was being managed well by others. And so I thought, well, I've always, maybe not always, but for a while, I'd wanted to run around the world and thought that was a good time to do it.

So I took initially two years off expecting to go back. But in the meantime, the management of the former wave energy company ran it into the ground and ended up in insolvency. So I didn't have a job to go back to, and then, a few years later, I had a new idea about the technology behind Wave Swell; I describe it as a light bulb moment. And so, a friend and I decided to form Wave Swell Energy. We convinced a couple of others we knew to join us, and here we are. It looks like we'll be making wave energy commercially viable for the first time.

Elena: Wow, thank you for sharing that with me. It's interesting to hear how things developed in your professional life and what led you from one phase to the next. Now, you took two years off to run around the world, literally around the world. And you wrote a book about it, The World At My Feet, where you narrate your experience. But I wanted to ask you, how did that experience influence you, your work, or your views on the world, climate change, and the environment? Did it have any influence like that?

Dr. Denniss: Well, yeah. I mean, I think it has to have. I didn't do it for some sort of cathartic, emotional experience. I just thought it was a great adventure. And it certainly was. It gave me a lot of time to think. And I dare say that I managed to get a little clearer on ideas around wave energy, although the concept that led to Wave Swell didn't happen until just prior to the company’s foundation several years later.

As far as climate change is concerned, I did see some reasonably wild weather in the U.S. at the time when I was running through Illinois in the middle of July, roughly about this time, actually it was exactly at this time. And I struck some very, very hot days. It was apparently the hottest summer ever recorded in the U.S. at the time. So I don't know whether that record has been beaten since. It probably has. But it was clear that there was some really extreme weather events that were happening, and that sort of crystallized my understanding of the reality of climate change. And, thankfully, I managed to spend a lot of my time more towards the winters in locations rather than the summers. But I had to get through that particularly hot middle of summer.

Dr. Denniss in Colorado, during his run around the world Source: Tom's Next Step


Elena: That must have been hard, to run in such extreme heat.


Dr. Denniss: Yeah, I'm not sure if you're aware, but temperatures are usually measured in the shade, and there's a good reason for that. For when you actually are out in the direct sunlight, it's a lot hotter. You know, it can be, well, you're used to Fahrenheit, I guess. And so it can probably be 15 or 20 degrees Fahrenheit higher in the sun, or more, actually, probably 15 to twenty five degrees more than what you you're measuring in the shade. I took two different types of thermometers, one to begin with, and I wasn't sure if it was reading correctly, so I got a completely different one. And they were consistent with each other, but twice they measured one hundred and forty degrees Fahrenheit in the direct sun. And that was what I was running in. That's why it was so difficult.


Elena: Oh, I can't imagine what that was like.

Dr. Denniss: Well, particularly doing 50 kilometers a day through sort of the middle of the day. Several times, policemen in cars pulled up and said, are you all right? You're crazy. And I'd have to tell them what I was doing.


Elena: That's a good anecdote! The last thing I would like to ask you is, if you were to talk to a younger version of yourself, what kind of advice would you give yourself about your career and your life in general. Any advice that you would have appreciated back then, and that maybe you would like to share with young people now.

Dr. Denniss: Well, it's not advice that would have changed what I would have ended up doing. I'd want to confirm that it was OK to do what I ended up doing. Don't do anything that you don't enjoy. A career is too long a time to be turning up every day, not enjoying what you've been doing. So it's important to find something that you do enjoy. That might mean not being paid as much, but it's better to have a lesser income and enjoy going to work every day than the reverse. So my advice would be just, whatever you want to do, if it interests you, do it, and if you want to change at a later time, do that, do that as well. And that's what I've done. I don't think you're locked in forever. Just because you've done a degree in a certain subject, that doesn't mean you have to work in that subject area for the rest of your life. There's so many options, so many ways of getting from one place to another, and you can change your path along the way.


Elena: Thank you, Dr Denniss. Thank you so much for taking the time to talk to me, and for your openness. It's been an honor.


For more information on Wave Swell Energy's technology, visit their website.


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